The work outlined in this proposal consists of an immunological analysis of glycosaminoglycans and proteoglycans. This analysis focuses on defining the cellular distribution these molecules and the roles they play in the development of the cerebellum. Glycosaminoglycans and proteoglycans are prominent components of the nervous system but their precise distribution and function is not understood. Since specific histological probes do not exist for this highly heterogenous group of macromolecules, they have been difficult to study. We have recently generated monoclonal antibodies to glycosaminoglycans and proteoglycan complexes using novel immunization procedures designed to minimize immunodominance and suppression. These methods will be refined and extended to focus on glycosaminoglycans and proteoglycans from cerebellum. The mouse cerebellum will be studied because of the large amount of information available concerning its development. Monoclonal antibodies specific for each type of glycosaminoglycan and for proteoglycans will be generated and used to localize these molecules in situ to determine their distribution in the developing cerebellum. Individual antigens will be purified using biochemical and immunoaffinity techniques and their properties determined. Antigens will be localized in primary cultures to identify the types of cells that synthesize each molecule. We have recently produced a monoclonal antibody to a heparan sulfate proteoglycan complex that blocks neurite outgrowth in culture. Since this antibody binds to cerebellum, it will be used to study this antigen and investigate its function. In a similar way, new antibodies will be tested for their ability to interfere with such properties as cell survival, adhesion, aggregation and neurite outgrowth.